ZR/V multi-site olefin polymerization catalyst

ABSTRACT

A catalyst useful in the polymerization of olefins, especially ethylene, is disclosed. The catalyst is obtained by admixing a zinc composition, a zirconium composition and a vanadium composition. The catalyst may be combined with a co-catalyst and, optionally, a modifier to yield an olefin polymerization system. The catalyst exhibits extremely high activity, good hydrogen response and produces polymers having broad molecular weight distribution (&#34;MWD&#34;) and manifesting bimodal MWD profile.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The instant invention is directed to a catalyst useful in thepolymerization of olefins, particularly homopolymerization andcopolymerization involving ethylene. Specifically, the instant inventionis directed to a catalyst comprised of a zirconium composition, avanadium composition and an activator. The instant invention isparticularly useful in producing an ethylene homopolymer having a broadmolecular weight distribution (MWD), a bimodal molecular weightdistribution profile, and a unique combination of physical properties,all in a single reactor.

2. Description of the Prior Art

The polymerization of olefins using transition metal catalysts is wellestablished in the art. Polymerizations employing these catalystsproduce polyolefins possessing desired characteristics in high yield,usually at processing conditions of low temperature and low pressure,thus making these catalysts the subject of much research. An especiallyimportant class of catalysts where improvement is sought is that classof catalysts which produce ethylenic and/or alpha-olefinic polymers,particularly the commercially important polymer, polyethylene.

Of practical interest is the development of a catalyst which will yieldpolymer adaptable for use in high strength films and light weight blowmolding resins. Generally, these characteristics are indicative of apolymer having a broad molecular weight distribution. The usual measureof the dispersity of the molecular weight distribution in the art hasbeen the ratio of the weight average molecular weight to the numberaverage molecular weight. A distribution is said to be narrow if for agiven polymer type of constant average molecular weight, the numberaverage molecular weight is substantially the same as the weight averagemolecular weight. As the ratio of weight average molecular weight tonumber average molecular weight increases from over 1:1, thedistribution becomes broad. Generally, as the distribution becomesbroad, film strength and resin processability improve. Thus inapplications where these traits are of concern, a broad molecular weightdistribution is desirable.

To further modify the physical characteristics and performanceproperties of a polymer, the shape of the molecular weight distributioncurve can be varied. One technique of varying the molecular weight sothat it becomes broadened is by making the distribution polymodal, i.e.,making the polymer appear as though it consists of two (bimodal) orthree (trimodal) distinct polymers. By controlling the location andconcentration of the modes, the molecular weight distribution may bevaried and different processing and end-use properties may be obtained.To achieve these results special catalyst systems must be used.

To attain these properties, as desired, the common practice heretoforehas entailed the use of multiple reactors, such as in a cascade system,and, as necessary, the employment of different catalysts in the reactorsequence so to produce the sought-after polymer characteristics. Becauseof the complexity and cost of such processing, as correlates for exampleto the number of reactors required, the necessity of different catalystsetc., the art recognizes a continuing need of producing theaforementioned polymer characteristics without multiple reactors ormultiple catalysts.

Though desirable, the art has been unable to develop an entirelysatisfactory catalyst able to produce, in a single reactor, a polymerhaving the requisite properties while at the same time evincing highactivity, i.e., leaving low catalyst residue in the product, goodhydrogen response (to facilitate control of molecular weight),minimization of low molecular weight tail so as to eliminate odor orsmoke problems that often occur in downstream processing, and notrequiring a substantial amount of promoter.

SUMMARY OF THE INVENTION

A new catalyst has now been developed which exhibits high activity andproduces, in a single reactor, olefin polymers having a broad molecularweight distribution characterized by a bimodal molecular weightdistribution profile. The use of a single reactor alleviates gelproblems caused by undispersed resin and is cost effective byeliminating the need to redesign current reactors, employ two or moreexisting reactors in a cascade system, or to construct a new cascadereactor system. The present invention obtains a polymer having a broadmolecular weight distribution with a bimodal characteristic by using acatalyst having two types of active centers: one center having, e.g., alow sensitivity to hydrogen as a chain transfer agent resulting in avery low melt index polymer; the other having, e.g., an extremely highsensitivity to hydrogen resulting in a very high melt index polymer. Acatalyst having two types of active centers is denoted in thisspecification as a dual site catalyst.

In accordance with the present invention, a catalyst is provided whichcomprises the product obtained by admixing a zirconium compositionhaving the formula ZrX_(a) ¹ (OR¹)_(4-a) wherein X¹ is halogen, R¹ ishydrocarbyl having 1 to about 18 carbon atoms and a is 0 or an integerfrom 1 to 4, or mixtures thereof; and a vanadium composition selectedfrom the group consisting of compounds having the formula VX_(c) ²(OR²)_(b-c) wherein X² is halogen, R² is hydrocarbyl having 1 to about18 carbon atoms, b is the valence of vanadium and is 3 or 4 and c is 0or an integer from 1 to b, VOX_(d) ³ (OR³)_(3-d) wherein X³ is halogen,R³ is hydrocarbyl having 1 to about 18 carbon atoms and d is 0 or aninteger from 1 to 3, VOX₂ ⁴ wherein X⁴ is halogen, or mixtures thereof;and an activator selected from the group consisting of compounds havingthe formula ZnX₂ ⁵ . 2AlR₃ ⁴ wherein X⁵ is halogen, R⁴ is hydrocarbylhaving 1 to about 12 carbon atoms, or MR_(e) ⁵ X_(3-e) ⁶ wherein M isaluminum or boron, X⁶ is halogen, R⁵ is hydrocarbyl having 1 to about 12carbon atoms and e is 0 or an integer from 1 to 3, or Al₂ R₃ ⁶ X⁷wherein R⁶ is hydrocarbyl having 1 to about 12 carbon atoms and X⁷ ishalogen, or MgR_(f) ⁷ Y_(2-f) wherein R⁷ is hydrocarbyl having 1 toabout 12 carbon atoms, Y is halogen or has the formula OR⁸ wherein R⁸ ishydrocarbyl having 1 to 12 carbon atoms or Y is a silyl amide having theformula N(SiR₃ ⁹)₂ wherein R⁹ is hydrocarbyl having 1 to about 12 carbonatoms and f is 0, 1 or 2, or mixtures thereof.

In further accordance with the present invention, an olefinpolymerization process is provided.

In this process, olefins such as ethylene and/or one or morealpha-olefins are contacted with the above-defined catalyst, aco-catalyst and, optionally, a modifier under polymerization conditionseffective to obtain a homopolymer or copolymer.

The olefin polymerization catalyst system of the present invention isuseful in gas phase, slurry and solution polymerization processes andfinds particular utility in producing ethylene homopolymer, or acopolymer of ethylene and one or more alpha-olefins. The polymer thusproduced has high molecular weight and a broad molecular weightdistribution.

BRIEF DESCRIPTION OF THE DRAWING

The Figure illustrates the bimodal molecular weight distributiontypically obtained in slurry homopolymerization of ethylene utilizingthe catalyst of the present invention. The catalyst in this particularpolymerization was the product obtained by admixing ZnCl₂ . 2Al(C₂ H₅)₃,ZrCl₂ (OC₄ H₉)₂, and VO(OC₄ H₉)₃ in a molar ratio of 12:1:5,respectively.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention a catalyst is provided.Although not required in the practice of the present invention, ahydrocarbon solvent may be employed as a medium for the preparation ofthe instant catalyst. Non-polar solvents, e.g., alkanes (such as hexaneand heptane), cycloalkanes and aromatics are preferred. If a solvent isemployed, it is preferred that the solvent is dried in order to removewater. Drying in this regard may be accomplished by techniques known inthe art, e.g., by molecular sieve. The solvent may be allowed to remainthroughout preparation of the catalyst and can be removed byconventional means, such as decantation, filtration or evaporation.

The catalyst of the present invention is the product obtained byadmixing a zirconium composition, a vanadium composition and anactivator, all as defined hereinbelow. It should be appreciated that noparticular sequence of admixing is required and that the presentinvention contemplates simultaneous admixing as well as any combinationof sequential admixing.

If other than simultaneous admixing is utilized, no specific time periodneed elapse between the addition of any one or more of the zirconiumcomposition, vanadium composition and activator. If sequential admixingis employed, it is preferred that about 30 minutes elapse betweenadditions.

Stirring, although not necessary, is also preferred.

The zirconium composition useful in the practice of the presentinvention has the formula ZrX_(a) ¹ (OR¹)_(4-a) wherein X¹ is halogen,R¹ is hydrocarbyl having 1 to about 18 carbon atoms and a is 0 or aninteger from 1 to 4. Preferably, R¹ has 2 to about 10 carbon atoms. As ahydrocarbyl, R² is preferably alkyl, and depending on the number ofcarbon atoms, cycloalkyl, aryl, aralkyl or alkaryl. X¹ is preferablychlorine. Examples of preferred zirconium compositions include ZrCl₄,ZrCl₂ (OC₄ H₉)₂, Zr(OC₃ H₇)₄ and Zr(OC₄ H₉)₄.

Mixtures of zirconium compositions may also be used in the practice ofthe present invention.

The vanadium composition useful in the instant invention has the formulaVX_(c) ²)OR²)_(b-c) wherein X² is halogen, R² is hydrocarbyl having 1 toabout 18 carbon atoms, b is the valence of vanadium and is 3 or 4 and cis 0 or an integer from 1 to b. Preferably, R² has 2 to about 6 carbonatoms. As a hydrocarbyl, R² is preferably alkyl, and depending on thenumber of carbon atoms, cycloalkyl, aryl, aralkyl or alkaryl. X² ispreferably chlorine. An example of a preferred vanadium compound havingthis formula is VCl₄.

A vanadium composition also useful in the practice of the presentinvention has the formula VOX_(d) ³ (OR³)_(3-d) wherein X³ is halogen,R³ is hydrocarbyl having 1 to about 18 carbon atoms and d is 0 or aninteger from 1 to 3. Preferably, R³ has 2 to about 6 carbon atoms. As ahydrocarbyl, R³ is preferably alkyl, and depending on the number ofcarbon atoms, cycloalkyl, aryl, aralkyl or alkaryl. X³ is preferablychlorine. Examples of preferred vanadium compounds having thisparticular formula include VOCl₃, VO(iOC₃ H₇)₃ and VO(OC₄ H₉)₃.

Another vanadium composition useful in the present invention has theformula VOX₂ ⁴ wherein X⁴ is halogen; an example of a preferred vanadiumcompound in this regard is VOCl₂.

Mixture of vanadium compositions may also be used in the practice of theinstant invention.

An activator useful in the practice of the present invention has theformula ZnX₂ ⁵ . 2AlR₃ ⁴ wherein X⁵ is halogen and R⁴ is hydrocarbylhaving from 1 to about 12 carbon atoms; preferably 2 to 6 carbon atoms.As a hydrocarbyl, R⁴ is preferably alkyl, and depending on the number ofcarbon atoms, cycloalkyl, aryl, aralkyl or alkaryl. X⁵ is preferablychlorine. An example of an activator in this regard is ZnCl₂ . 2Al(C₂H₅)₃.

An activator having this formula may be prepared by contacting a zinchalide with an aluminum hydrocarbyl. Preferably, in the practice of thisembodiment, about one mole of zinc halide is contacted with about twomoles of aluminum hydrocarbyl. Contact in this regard may occurseparately, i.e., before admixture with any of the othercatalyst-forming components, or it may occur in situ upon the additionof sufficient quantities of zinc halide and aluminum hydrocarbyl to thecatalyst admixture. Heating may be required, as necessary, to dissolvethe zinc halide. The activator thus formed, in either case, is solublein non-polar solvents such as heptane. A preferred zinc halide is zincchloride; a preferred aluminum hydrocarbyl is aluminum alkyl, morepreferably triethyl aluminum.

Another activator useful in the practice of the present invention hasthe formula MR_(e) ⁵ X_(3-e) ⁶ wherein M is aluminum (Al) or boron (B),R⁵ is hydrocarbyl having 1 to about 12 carbon atoms, X⁶ is halogen and eis 0 or an integer from 1 to 3. Preferably, R⁵ has 2 to about 6 carbonatoms. As a hydrocarbyl, R⁵ is preferably alkyl, and depending on thenumber of carbon atoms, cycloalkyl, aryl, aralkyl or alkaryl. X⁶ ispreferably chlorine. Examples of activators having this formula includediethyl aluminum chloride ((C₂ H₅)₂ AlCl), ethyl aluminum dichloride (C₂H₅ AlCl₂), ethyl boron dichloride (C₂ H₅ BCl₂) and boron trichloride(BCl₃).

Still another activator useful in the practice of the present inventionhas the formula Al₂ R₃ ⁶ X₃ ⁷ wherein R⁶ is a hydrocarbyl having 1 toabout 12 carbon atoms and X⁷ is halogen. Preferably R⁶ has 2 to about 6carbon atoms. As a hydrocarbyl, R⁶ is preferably alkyl, and depending onthe number of carbon atoms present, cycloalkyl, aryl, aralkyl oralkaryl. X⁷ is preferably chlorine. An example of an activator havingthis formula is aluminum sesquichloride ((C₂ H₅)₃ Al₂ Cl₃).

Yet still another activator useful in the practice of the presentinvention has the formula MgR_(f) ⁷ Y_(2-f) wherein R⁷ is hydrocarbylhaving 1 to about 12 carbon atoms, Y is halogen, or has the formula OR⁸where R⁸ is hydrocarbyl having 1 to about 12 carbon atoms, or Y is asilyl amide having the formula N(SIR₃ ⁹)₂ where R⁹ is hydrocarbyl having1 to about 12 carbon atoms and f is 0, 1 or 2. A description ofcompounds conforming to this definition of Y is found in U.S. Pat. No.4,383,119 the contents of which are incorporated herein by reference.Preferably R⁷, R⁸ and R⁹ have 2 to about 6 carbon atoms, respectively.As hydrocarbyls, R⁷, R⁸ and R⁹ are preferably alkyl and depending on thenumber of respective carbon atoms, cycloalkyl, aryl, aralkyl or alkaryl.The preferred halogen is chlorine. Examples of activators having thisformula include dibutyl magnesium ((C₄ H₉)₂ Mg), butyl ethyl magnesium(C₄ H₉ MgC₂ H₅) and butyl magnesium silyl amide, e.g., C₄ H₉ MgN(Si(CH₃)₃)₂, also known as BMSA.

Mixtures of activators having the aforedescribed formulas may also beused in the practice of the invention.

The amount of zirconium composition, vanadium composition and activatorused in the preparation of the catalyst of the subject invention is mostconveniently stated as a molar ratio. Thus for about each mole ofzirconium composition, up to about 10 moles of vanadium composition andup to about 25 moles of activator may be utilized.

In a preferred practice of the invention, up to about 8 moles ofvanadium composition and up to about 17 moles of activator may beutilized for about each mole of zirconium composition. More preferably,for about each mole of zirconium composition, up to about 5 moles ofvanadium composition and up to about 12 moles of activator are employed.Still more preferably, for about each mole of zirconium composition, upto about 3 moles of vanadium composition and up to about 8 moles ofactivator are employed. Yet still more preferably, for about each moleof zirconium composition, up to about 2 moles of vanadium compositionand up to about 6 moles of activator are employed. More preferably, forabout each mole activator zirconium composition, up to about 1 mole ofvanadium composition and up to about 4 moles of activator are employed.

After admixing the zirconium composition, vanadium composition andactivator, the catalyst product thus obtained can be recovered. If asolvent has been employed, it is preferable to remove the same;techniques known in the art, e.g., decantation, filtration orevaporation may be used in this regard. If evaporation is employed, itis preferred that a nitrogen purge at a temperature of about 100° C. beutilized.

It should be appreciated that in the preferred practice of the presentinvention the catalyst is prepared under an inert atmosphere, such as anitrogen atmosphere. Furthermore, it is desirable that catalystpreparation be conducted under conditions that are substantially free ofoxygen. Thus in preferred practice, no more than 100 ppm of oxygen,based on the weight of the gaseous atmosphere, is present duringcatalyst preparation. More preferably, no more than 10 ppm of oxygen ispresent; most preferably, no more than 1 ppm of oxygen is present, basedon the weight of the gaseous atmosphere.

It is also desirable that catalyst preparation be conducted underconditions that are substantially free of water. Thus in a preferredpractice, no more than 5% by weight water, based on the weight of theadmixture, is present during catalyst preparation. More preferably, nomore than 0.5% by weight water, and most preferably no more than 0.05%by weight water is present, based on the weight of the admixture.

In practicing the present invention, the admixing generally occurs at orabout room temperature, e.g., about 20° C. to about 25° C., and at orabout atmospheric pressure. Thus no special heating or cooling and novacuum or pressurization are necessary. However, these may be employedwithout detriment and in certain embodiments of the present invention,one or the other is preferred.

More specifically, the preparation of certain embodiments of the presentinvention are facilitated by heating and/or cooling steps. For example,the zirconium compound Zr(OC₄ H₉)₄ when obtained commercially (e.g. fromDynamite-Nobel Chemical) has a certain amount of butanol (C₄ H₉ OH)associated with it. Similarly, there is residual alcohol present if, asin one embodiment of the present invention, ZrCl₄ is reacted with analcohol, e.g., butanol, to form a zirconium alkoxy and/or a zirconiumchloroalkoxy. In these circumstances, it is preferred practice to heatthe solution admixture in order to facilitate the interaction ofcomponents. Heating in this regard is preferably at a temperature of upto about 100° C., more preferably about 85°-90° C.

Moreover, in certain embodiments it is desirable to cool the admixtureprior to the final addition of either the vanadium composition,zirconium composition or activator. Cooling in this regard may beemployed when, for example, the final addition is found to be tooexothermic for convenient manipulation. Cooling is preferably totemperature at or about 0° C.

While the catalyst product obtained after admixing the catalyst-formingcomponents need not be washed, it is preferred practice to do so,preferably with the solvent in which admixing occurred, if a solvent wasused. Preferably, washing is repeated more than once, e.g., three times.

The catalyst product thus obtained need not be dried prior to use,especially if slurry polymerization is contemplated, but may be driedwithout detriment. If drying is performed, it is preferably done at atemperature of about 100° C. with a nitrogen purge for approximatelythirty minutes.

The product obtained by the aforedescribed procedure represents thecatalyst of the instant invention, which when combined with aco-catalyst forms an olefin polymerization catalyst system. Co-catalystsuseful in the practice of this aspect of the present invention includemetal alkyls, metal alkyl hydrides, metal alkyl halides, or metal alkylalkoxides, the metal being aluminum, boron, zinc, or magnesium and thealkyl having 1 to about 12 carbon atoms, preferably 2 to about 6 carbonatoms; mixtures of co-catalyst may also be employed. Preferredcocatalysts include aluminum trialkyls with triethylaluminum and/ortri-isobutyl-aluminum especially preferred.

Co-catalyst is generally utilized in an amount that conforms to a molarratio of co-catalyst to zirconium composition of about 1:1 to about200:1; a more preferred ratio is about 1:1 to about 50:1. The catalystand the co-catalyst may be added continuously to the polymerizationrector during the course of the polymerization to maintain the desiredratio.

Modifiers, sometimes referred to as "promoters" in the art, aretypically chosen for their ability to increase and maintain thereactivity of vanadium catalyst, and also affect melt index and meltindex ratio (MIR), which is a measure of molecular weight distribution.

Useful modifiers include halogenating agents such as those of theformula M¹ H_(g) X_(h-g) ⁸ wherein M¹ is Si, C, Ge or Sn (preferably Sior C, and most preferably C), X⁸ is halogen (preferably Cl or Br andmost preferably Cl), g is 0, 1, 2 or 3, and h is the valence of M¹. Suchmodifiers are disclosed in Miro, et al. U.S. Pat. No. 4,866,021 (Sep.12, 1989), the disclosure of which is incorporated herein by reference.Modifiers of this type include chloroform, carbon tetrachloride,methylene chloride, dichlorosilane, trichlorosilane, silicontetrachloride, and halogenated hydrocarbons containing 1 to 6 carbonatoms such as those available from E. I. duPont de Nemours & Co. underthe trade designation Freon (e.g., Freon 11 and Freon 113).

Bachl, et al. U.S. Pat. No. 4,831,090 (May 16, 1989), the disclosure ofwhich is incorporated herein by reference, discloses several classes oforganohalogen compounds which are useful as modifiers. These includesaturated aliphatic halohydrocarbons, olefinically unsaturated aliphatichalohydrocarbons, acetylenically unsaturated aliphatic halohydrocarbons,aromatic halohydrocarbons, and olefinically unsaturated halogenatedcarboxylates.

Particularly preferred modifiers are halocarbon compounds of the formulaR₁ ¹⁰ CS₄₋₁ ⁹ wherein R¹⁰ is hydrogen or an unsubstituted or halogensubstituted saturated hydrocarbon having from 1 to 6 carbon atoms; X⁹ ishalogen and i is 0, 1 or 2. Examples of these halocarbon compoundsinclude fluoro-, chloro-, or bromo-substituted ethane or methanecompounds having at least two halogens attached to the carbon atoms.Especially preferred modifiers include CCl₄, CH₂ Cl₂, CBr₄, CH₃ CCl₃,CF₂ ClCCl₃, with the most especially preferred being CHCl₃ (chloroform),CFCl₃ (Freon 11) and CFCl₂ CCF₂ Cl (Freon 113). Mixtures of any of thesemodifiers may be used.

Selection of modifiers can be used to adjust polymer properties,sometimes at the expense of activity.

Preferred polymer properties may be obtained with a chosen modifier at aratio of modifier to transition metal which is a compromise to maximumcatalyst activity. The product molecular weight distribution andresponse of melt index to the presence of hydrogen are tunable by choiceand concentration of modifier. Activity, melt index ratio (MIR), highload melt index (HLMI), etc. all vary with the ratio of modifier totransition metal, and with the choice of modifier.

The modifier utilized, when it is utilized, is present in an amount thatcorresponds to a ratio of modifier to vanadium composition of about0.1:1 to about 1000:1 (mole:mole), preferably about 1:1 to about 100:1,and more preferably about 5:1 to about 50:1.

The polymerization reaction may be conducted under solution, slurry orgas phase (including fluidized bed) conditions, at a temperature ofabout 50° to about 250° C.; preferred temperature is about 50° to 110°C.; more preferred temperature is about 65° to about 105° C. Pressure isfrom about ambient to about 30,000 psi; preferred pressure is aboutambient to about 1,000 psi; more preferred pressure is about ambient toabout 700 psi.

The polymer obtained by the process of the present invention may be ahomopolymer of ethylene, a homopolymer of an alpha-olefin, a copolymerof two or more alpha-olefins, or a copolymer of ethylene and one or morealpha-olefins, said alpha-olefins having 3 to about 12 carbon atoms.Alpha-olefins particularly useful in the present invention includepropylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1,3-butadiene and1,5-hexadiene.

The polymer thus produced can have a melt index (MI) at 190° C. and 2.16kg (as measured by ASTM D1238-82) as high as up to about 1000, and aslow as about 0.01 or less. The melt index ratio (HLMI/MI, alsodenominated as MIR) of the polymer capable of being produced will varydepending on the above parameters of HLMI and MI; for example, theHLMI/MI may be between about 30:1 to about 400:1, preferably betweenabout 40:1 to about 400:1 and more preferably between about 50:1 toabout 400:1. As appreciated by those of skill in the art, the melt indexratio correlates to molecular weight distribution (MWD).

The polymer produced by the catalyst of the present invention does notrequire polymer de-ashing to be commercially acceptable in low ashpolymer applications.

The polymer of the present invention also exhibits a bimodal molecularweight distribution profile, as when examined by gel permeationchromatography with 1,2,4 trichlorobenzene as a solvent.

The following examples are illustrative of the scope of the presentinvention and are not intended as a limitation thereon.

EXAMPLE 1 Preparation of Activator

Activator was prepared from zinc dichloride (ZnCl₂) and triethylaluminum (Al(C₂ H₅)₃). The preparation was carried out under an N₂atmosphere. Heptane was used as a solvent.

Zinc dichloride (34.05 grams; the corresponding concentration was about0.25 moles) was placed into a Fisher-Porter bottle in a dry glove box. Asolution of triethyl aluminum (320.5 milliliters, the correspondingconcentration was about 0.5 moles), in heptane, was subsequently added;the ratio of zinc to aluminum was 1:2. The solution was heated to 90° C.for 2 hours, with stirring. After the heating, the solid ZnCl₂ dissolvedto form the activator, which was soluble in the heptane. The activator,ZnCl₂ . 2Al(C₂ H₅)₃, was used without any further purification.

EXAMPLE 2 Catalyst Preparation

A catalyst composition of VOCl₃, Zr(OC₄ H₉)₄ . nC₄ H₉ OH, and ZnCl₂ .2Al(C₂ H₅)₃ was prepared. The molar ratio of these catalyst components,in the order listed, was about 1:1:4.

Into a three-neck round bottom flask fitted with a paddle stirrer andpurged with a N₂ was placed heptane (50 mls) and then VOCl₃ (10 mls of a1M solution, the corresponding concentration was about 0.01 moles).Zr(OC₄ H₉)₄ . nC₄ H₉ OH was obtained from Dynamite-Nobel Chemical; n wascalculated to be 1.3. This viscous zirconium compound was added (4.35ml, the corresponding concentration was about 0.01 mole) in dropwisefashion to the VOCl₃ solution. The solution turned an orange-yellowcolor and was opaque. The solution was heated to 85° C. for 30 minutes,with stirring, after which time the solution had turned a light brownand had become clear, and no acid was detected in the N₂ gas purgeeffluent. The solution was then chilled to 0° C.

To the chilled solution was slowly added ZnCl₂ . 2Al(C₂ H₅)₃ (51.3 ml,the corresponding concentration was about 0.04 mole), prepared inaccordance with Example 1. The light brown solution turned a dark brown;a light color precipitate formed. The slurry was then warmed to roomtemperature. The solid catalyst--the precipitate--was washed three timeswith heptane (120 mls per wash) and recovered.

EXAMPLE 3

A catalyst composition of ZrCl₄, ZnCl₂ . 2Al(C₂ H₅)₃ and VO(OC₄ H₉)₃ wasprepared. The molar ratio of these catalyst components, in the orderlisted, was about 1:4:1.

Into a three-neck round bottom flask fitted with a paddle stirrer andpurged with N₂ was placed ZrCl₄ (3.92 grams, the correspondingconcentration was about 0.0168 mole) and heptane (30 mls). A peach colorslurry formed. To the slurry was added C₄ H₉ OH (3.11 ml, thecorresponding concentration was about 0.0336 mole), slowly, in adropwise fashion, at room temperature (20°-25° C.). The peach colorslurry turned white. The solution became clear 15 minutes later. Somepeach color precipitate was observed and acid was detected in the N₂purge gas effluent.

The three-neck flask was heated to 85° C. and stirred for 30 minutes,after which time an oily brown liquid layer was observed at the bottom;the solid precipitate had disappeared. ZnCl₂ . 2Al(C₂ H₅)₃, prepared inaccordance with Example 1, was slowly added (86.2 ml, the correspondingconcentration was about 0.0672 mole). A brown slurry was formed. Theslurry was stirred, at room temperature, for 30 minutes. VO(OC₄ H₉)₃ wasadded (16.8 ml, the corresponding concentration was 0.0168 mole) slowly,in dropwise fashion. A dark brown precipitate was formed, and the liquidlayer had a light brown color. The slurry was stirred, at roomtemperature, for 30 minutes. The solid precipitate was then washed threetimes with heptane (120 mls per wash) to recover the solid catalyst).

EXAMPLE 4

A catalyst composition of ZrCl₄, ZnCl₂ . 2Al(C₂ H₅)₃, VO(OC₄ H₉)₃ wasprepared. The molar ratio of these catalyst components, in the orderlisted, was about 1:8:3.

Into a three-neck round bottom flask fitted with a paddle stirrer andpurged with a N₂ was placed ZrCl₄ (2.13 grams; the correspondingconcentration was about 0.00914 mole) and heptane (50 mls). C₄ H₉ OH wasadded (1.69 mls; the corresponding concentration was about 0.01828mole). The resulting solution was heated to 90° C. with stirring for 30minutes, at the end of which time the top layer of the solution wasobserved to be clear; the bottom layer was observed as having a darkyellow color. The solution was then cooled to room temperature.

ZnCl₂ . 2Al(C₂ H₅)₃, prepared in accordance with Example 1, was slowlyadded to the solution (9.37 mls; the corresponding concentration wasabout 0.7312 mole). The solution was observed to turn milky and thendark brown. The solution was stirred at room temperature for 30 minutes,then chilled to 0° C. VO(OC₄ H₉)₃ was added in dropwise fashion and abrown slurry was formed. The slurry was warmed to room temperature andstirred for 1 hour. The solid precipitate from the slurry was washedfour times with heptane (125 mls per wash) to recover the solidcatalyst.

EXAMPLE 5

A catalyst composition of ZrCl₄, ZnCl₂ . 2Al(C₂ H₅)₃, VO(OC₄ H₉)₃ wasprepared. The molar ratio of these catalyst components, in the orderlisted, was about 1:12:5.

Into a three-neck round bottom flask fitted with a paddle stirrer andpurged with N₂, was placed ZrCl₄ (1.38 grams; the correspondingconcentration was about 0.005918 mole) and heptane (50 mls). C₄ H₉ OHwas added (1.10 mls; the corresponding concentration was about 0.011836mole) and the solution was heated with stirring at 90° C. for 1 hour. Atthe end of this time, the top layer of the solution observed to beclear, and the bottom layer a dark yellow color. The solution was cooledto room temperature and ZnCl₂ . 2Al(C₂ H₅)₃, prepared in accordance withExample 1, was added (91.0 mls; the corresponding concentration wasabout 0.071 mole). The solution was observed to turn milky with thefirst 6 mls; it then turned yellow and clear brown, then dark brown uponcompletion of the addition of the zinc complex. A light brownprecipitate had formed. The solution was stirred at room temperature,then chilled to 0° C. with an ice bath. VO(OC₄ H₉)₃ was added (29.6 mls;the corresponding concentration was about 0.02959 mole) in dropwisefashion over a period of 10 minutes. The solution was then stirred for 1hour. The resultant catalyst was washed four times with heptane (125 mlsper wash) and recovered.

EXAMPLE 6

A catalyst composition of Zr(OC₄ H₉)₄ . nC₄ H₉ OH, VOCl₃, ZnCl₂ . 2Al(C₂H₅)₃ was prepared. The molar ratio of these catalyst components, in theorder listed, was about 1:2:6. In this preparation, Zr(OC₄ H₉)₄ wasprereacted with VOCl₃ overnight before the activation treatment.

Into a Fisher-Porter bottle at room temperature was placed 3.48 mls ofZr(OC₄ H₉)₄ . nC₄ H₉ OH (commercially obtained from Dynamite-NobelChemical; n was calculated to be about 1.3, the correspondingconcentration was about 0.008 mole) and VOCl₃ (16 mls, the correspondingconcentration was about 0.016 mole). The solution was stirred for 30minutes, after which time a clear yellow solution with no precipitatewas observed. The solution was allowed to stand overnight (approximately15 hours) at room temperature, after which time the solution wasobserved to be clear and, brown in color; no precipitate was seen.

To this solution, ZnCl₂ . 2Al(C₂ H₅)₃, prepared in accordance withExample 1, as slowly added (61.5 mls, the corresponding concentrationwas about 0.048 mole). The addition was at room temperature and uponcompletion, a greenish brown precipitate in a brown solution wasobserved. The precipitate was washed three times with heptane (150 mlsper wash) and the solid, greenish-brown catalyst was recovered.

EXAMPLE 7

A catalyst composition of Zr(OC₄ H₉)₄ . nC₄ H₅ OH, ZnCl₂ . 2Al(C₂ H₅)₃,and VOCl₃ was prepared. The molar ratio of these catalyst components, inthe order listed, was about 1:6:2. In this catalyst preparation, thezirconium composition was not pre-reacted with the vanadium composition.

Into a Fisher-Porter bottle was placed 3.5 mls of Zr(OC₄ H₉)₄ . nC₄ H₅OH (commercially obtained from Dynamite-Nobel Chemical; n was calculatedto be about 1.3 mole, and heptane (50 mls). To this solution was added,at room temperature (20°-25° C.) ZnCl₂ . 2Al(C₂ H₅)₃, (61.5 mls, thecorresponding concentration was about 0.048 mole), prepared inaccordance with Example 1. The addition, with stirring, was fast andresulted in a clouded solution that was observed to be yellow, thenbrown, and finally formed a brown solution with brown precipitate.

After 30 minutes at room temperature had passed, VOCl₃ (16 mls, thecorresponding concentration was about 0.016 mole) was slowly added withfast stirring. Smoke was generated in the first 10 minutes. After 1 hourat room temperature a yellow-brown slurry was observed. After a firstheptane wash (150 mls), the filtrate was observed to react with air toform a white precipitate. After a second heptane wash (150 mls) thefiltrate was observed to still be reactive with air. After a third andfourth heptane wash (150 mls per wash), a yellowish-brown solid catalystwas recovered.

EXAMPLE 8

A catalyst composition of ZrCl₄, ZnCl₂ . 2Al(C₂ H₅)₃ and VOCl₃ wasprepared. The molar ratio of these catalyst components, in the orderlisted was about 1:6:2.

Into a Fisher-Porter bottle was placed ZrCl₄ (1.75 grams, thecorresponding concentration was about 0.0075 mole) and heptane (50 mls).While at room temperature, C₄ H₉ OH was slowly added (1.29 mls, thecorresponding concentration was about 0.015 mole). No observablereaction occurred at room temperature. The solution was heated at 90° C.for 1 hour, after which time the ZrCl₄ was observed to have disappeared,the resultant solution was a clear and yellow color, and had two layers.

The solution was cooled to room temperature with slow stirring and ZnCl₂. 2Al(C₂ H₅)₃ prepared in accordance with Example 1, was slowly added(57.7 mls, the corresponding concentration was about 0.045 mole) whilethe solution was slowly stirred. The solution color was observed to turnbrown in approximately 3 minutes and a brown precipitate was observed.After 30 minutes at room temperature, VOCl₃ (15 mls, the correspondingconcentration was about 0.015 mole) was slowly added. White smoke wasgenerated and the solution was stirred at room temperature for 1 hour. Abrown slurry was observed. The solid was washed three times with heptane(150 mls per wash) and a brown color solid catalyst was recovered.

EXAMPLE 9

A catalyst composition of Zr(OC₃ H₇)₄, ZnCl₂ . 2Al(C₂ H₅)₃, and VOCl₃was prepared. The molar ratio of the catalyst components, in the orderlisted, was about 1:6:2.

Zr(OC₃ H₇)₄ . nC₃ H₇ OH was commercially obtained from Alfa Chemical, nwas calculated to be about 1.58. Into a Fisher-Porter bottle was placedthe Zr(OC₃ H₇)₄ . nC₃ H₇ OH (3.22 mls, the corresponding concentrationwas about 0.008 mole) and heptane (50 mls). Fast addition of ZnCl₂ .2Al(C₂ H₅)₃, prepared in accordance with Example 1, followed (61.5 mls,the corresponding concentration was about 0.048 mole). The fast additionoccurred at room temperature and was followed by slow stirring for 15minutes. A brown solution with a brown precipitate was observed.

VOCl₃ was slowly added (16 mls, the corresponding concentration wasabout 0.016 mole) to this solution, at room temperature, and a solutionwith a brown precipitate was observed. After three washings with heptane(150 mls per wash), a solid brown catalyst was recovered.

EXAMPLE 10

A catalyst composition of ZrCl₄, C₄ H₅ OH, ZnCl₂ . 2Al(C₂ H₅)₃ and VOCl₃was prepared. The molar ratio of the catalyst components in the orderlisted was about 1:2:8:3.

Into a 500 ml, 3-neck round bottom flask was added 1.47 g of ZrCl₄ and50 mls heptane. With stirring, 1.17 mls of C₄ H₅ OH was added (the C₄ H₅OH:Zr mole ratio was 2). The mixture was stirred at 90° C. until a clearlight yellow solution formed. The solution was cooled to roomtemperature.

Next, 64.6 mls of ZnCl₂ . 2Al(C₂ H₅)₃, prepared in accordance withExample 1, was added dropwise at room temperature. The mixture was thenstirred at room temperature for 30 minutes, during which time aprecipitate formed. To this mixture, 18.9 mls of a 1.0 mM/ml solution ofVOCl₃ in heptane was added. This mixture was stirred for about 30minutes, then filtered, then washed three times with heptane (150 mlsper wash). The final catalyst solid was brown.

EXAMPLE 11 Polymerization

Homopolymers of ethylene were prepared using the catalyst of the presentinvention. Polymerization was conducted in an autoclave of approximately1.3 liters in size, and fitted with a stirrer. In each of thepolymerizations the reactor was purged with N₂ at a temperature greaterthan about 100° C. for about two hours. A solution of co-catalyst inheptane (about 0.5 mls of triethyl aluminum as a 25 weight percentsolution thereof in heptane) was added to the reactor at the desiredreaction temperature (about 80°-100° C.). The reactor was then closedand H₂ was added to the reactor from a pressure vessel. Isobutane wasadded (about 500 mls) and the stirrer in the reactor was turned on.Ethylene was then added to the reactor up to the desired operatingpressure (about 550 psi). Modifier was then injected at thepolymerization temperature, followed by the catalyst of the instantinvention about one minute later. Polymerization was run for about onehour. The reaction was terminated by shutting off the ethylene supplyand venting the reactor.

Table 1, below, identifies reaction conditions (temperature, ethylene,hydrogen, modifier), catalyst reactivity (in grams of polyethyleneproduced per gram of catalyst per hour, gPE/gCAT-hr) and MI, HLMI andMIR of the polymer produced for each run using the catalyst preparedaccording to Examples 3, 4, 5, 6, 7, 9 and 10.

                                      TABLE 1                                     __________________________________________________________________________    POLYMERIZATION DATA                                                                  C2H4 K2  Modifier                                                                             Modifier                                                                            Reactivity                                       Run                                                                              T (°C.)                                                                    Mole %                                                                             (psi)                                                                             Type   Micromoles                                                                          g PK/gCat-hr                                                                         MI HLMI                                                                              MIR                                __________________________________________________________________________    CATALYST OF EXAMPLE 3                                                          1 80.0                                                                              10.0 300 CHCl3  500   6240   0.02                                                                             1.7  84                                 2 80.0                                                                              10.0 300 CHCl3  2000  5330   0.02                                                                             2.4 105                                 3 80.0                                                                              10.0 400 CFCl3  500   6705   0.05                                                                             4.5  85                                CATALYST OF EXAMPLE 4                                                          4 80.0                                                                              10.0 200 CHCl3  200   4806   0.11                                                                             38.8                                                                              363                                 5 80.0                                                                              10.0 200 CHCl3  500   5712   0.64                                                                             168.3                                                                             265                                 6 80.0                                                                              10.0 200 CHCl3  1000  4604   0.26                                                                             78.9                                                                              307                                 7 93.3                                                                              8.5  200 CHCl3  500   8058   0.11                                                                             38.4                                                                              356                                 8 80.0                                                                              10.0 200 CFCl3  500   4647   0.57                                                                             167.8                                                                             296                                 9 80.0                                                                              10.0 200 Cl2FCCClF2                                                                           500   3856   -- 0.2 --                                 CATALYST OF EXAMPLE 5                                                         10 80.0                                                                              10.0 200 CHCl3  500   8040    1.66                                                                            239.9                                                                             145                                11 93.3                                                                              5.0  75  CHCl3  500   5940   1.29                                                                             168.4                                                                             132                                12 93.3                                                                              6.0  75  CHCl3  1000  10400  0.82                                                                             102.5                                                                             125                                13 93.3                                                                              6.0  75  CFCl3  500   8930   0.56                                                                             72.6                                                                              130                                14 93.3                                                                              6.0  75  CFCl3  100   14450  0.44                                                                             57.9                                                                              132                                15 80.0                                                                              10.0 150 CFCl3  100   11970  4.40                                                                             --  --                                 16 93.3                                                                              6.0  75  Cl2FCClF2                                                                            500   3300   -- 3.3 --                                 17 93.3                                                                              6.0  75  (CH3)3SiCl                                                                           500   1250   -- 0.1 --                                 CATALYST OF EXAMPLE 6                                                         18 93.3                                                                              7.0  100 CFCl3  100   12186  0.07                                                                             16.2                                                                              225                                19 93.3                                                                              7.0  100 CFCl3  200   10940  0.04                                                                             9.6 229                                20 93.3                                                                              7.0  100 CFCl3  400   10245  0.04                                                                             9.8 251                                21 93.3                                                                              7.0  150 CHCl3  200   10380  0.18                                                                             46.6                                                                              266                                22 93.3                                                                              7.0  100 CHCl3  200   11880  0.04                                                                             9.6 234                                23 93.3                                                                              7.0  100 CHCl3  400   1333   0.07                                                                             11.5                                                                              155                                24 93.3                                                                              7.0  100 CHCl3  200   7287   0.03                                                                             10.0                                                                              303                                25 93.3                                                                              7.0  100 CHCl3  200   9100   0.11                                                                             21.9                                                                              205                                26 93.3                                                                              7.0  100 CH2BrCl                                                                              100   53330  0.05                                                                             9.7 206                                27 93.3                                                                              7.0  100 CBr2F2 100   6713   0.08                                                                             22.3                                                                              297                                CATALYST OF EXAMPLE 7                                                         28 93.3                                                                              7.0  100 CFCl3  100   15200  -- 1.3 --                                 29 93.3                                                                              7.0  125 CFCl3  400   21840  -- 4.5 --                                 30 93.3                                                                              7.0  150 CFCl3  100   13642  -- 2.5 --                                 31 93.3                                                                              7.0  150 CFCl3  400   13033  0.01                                                                             4.1 293                                32 93.3                                                                              7.0  150 CFCl3  400   14050  -- 3.1.                                                                              --                                 33 93.3                                                                              7.0  200 CFCl3  400   17010  0.03                                                                             8.6 345                                34 93.3                                                                              7.0  175 CFCl3  800   12667  0.03                                                                             6.3 216                                35 93.3                                                                              7.0  200 CHCl3  400   17125  0.02                                                                             6.5 260                                36 93.3                                                                              7.0  200 CHCl3  100   12558  0.01                                                                             3.0 374                                37 93.3                                                                              7.0  175 CHCl3  800   16500  0.03                                                                             7.8 312                                CATALYST OF EXAMPLE 9                                                         38 93.3                                                                              7.0  100 CHCl3  100   8461   0.02                                                                             3.5 233                                39 93.3                                                                              7.0  100 CHCl3  400   5400   0.09                                                                             20.7                                                                              229                                40 93.3                                                                              7.0  100 CFCl3  100   8873   0.04                                                                             5.9 169                                41 93.3                                                                              7.0  100 CFCl3  400   6613   0.21                                                                             34.5                                                                              167                                42 93.3                                                                              7.0  100 CFCl3  400   7027   0.33                                                                             49.1                                                                              149                                43 99.0                                                                              7.0  70  CFCl3  400   5333   0.15                                                                             23.8                                                                              162                                44 99.0                                                                              7.0  70  CFCl3  400   10927  0.02                                                                             3.8 222                                CATALYST OF EXAMPLE 10                                                        45 93.3                                                                              7.0  100 CFCl3  100   15870  -- 2.0 --                                 46 93.3                                                                              7.0  200 CFCl3  100   8430   0.02                                                                             3.6 223                                47 93.3                                                                              7.0  200 CFCl3  400   14560  0.05                                                                             16.3                                                                              347                                48 93.3                                                                              7.0  200 CFCl3  400   9790   0.12                                                                             48  400                                49 93.3                                                                              7.0  200 CHCl3  400   12610  0.04                                                                             9.8 223                                50 93.3                                                                              7.0  200 CHCl3  800   13410  0.44                                                                             11.1                                                                              252                                __________________________________________________________________________

As seen from Table 1 above, the catalyst of Example 3 exhibited highreactivity with both CHCl₃ and CFCl₃ modifiers. Similarly, the catalystof Example 4, which had a vanadium to zirconium ratio of 3, exhibitedhigh reactivity which CHCl₃, CFCl₃ and Cl₂ FCCClF₂ as modifiers. Runnumber 7 in this regard showed particularly high catalyst reactivity atthe higher reaction temperature (about 93.3° C.).

The catalyst of Example 5, having a vanadium to zirconium ratio of 5,exhibited high reactivity with CHCl₃, CFCl₃, Cl₂ FCCClF₂ and (CH₃)₃ SiClas modifiers. Table 1 further shows that this catalyst was very reactiveeven at reduced levels of ethylene, i.e., at 5 and 6 mole %, as shown byRun numbers 11, 12, 13, 14, 16 and 17. A comparison of Run number 10using the catalyst of Example 5 with Run number 5 using the catalyst ofExample 4, wherein all other relevant conditions were substantially thesame, shows that the former had higher MI, greater reactivity and anarrower MWD as measured by MIR. Run numbers 10-17 further indicatethat, at least for the catalyst of Example 5, the use of CHl₃ and CFCl₃as modifiers gave higher MI potential than the use of Cl₂ FCCClF₂ and(CH₃)₃ SiCl.

Run numbers 18-27 in Table 1 utilized catalyst prepared in accordancewith Example 6 wherein the zirconium and vanadium compounds werepre-complexed prior to reaction with the activator compound; thevanadium to zirconium ratio was 2. Table 1 shows that this catalyst wasvery reactive when used in conjunction with CHCl₃, CFCl₃, CH₂ BrCl andCBr₂ F₂ as modifiers. The catalyst also produced a broad MWD as measuredby MIR. Run numbers 24 and 25 employed trihexyl aluminum and triethylaluminum, respectively, as cocatalysts; all other runs using thecatalyst of Example 6 employed tri-isobutylaluminum as cocatalyst.Generally, the use of triethylaluminum gave higher MI.

Run numbers 28-37 show polymerization data using catalyst preparedpursuant to Example 7. This catalyst had the same vanadium to zirconiumratio as the catalyst from Example 6; however, the zirconium andvanadium compounds were not pre-complexed. The catalyst of Example 7showed high reactivity with CHCl₃ and CFCl₃ as modifiers. A comparisonof Run numbers 18-27 using catalyst of Example 6 to Run numbers 28-37using catalyst of Example 7 shows that the former required less hydrogento yield similar MI. The polymer obtained using the catalyst of Example7 manifested broad MWD as evidenced by the high MIR. In addition, themolecular weight of the polymer was high, as gauged by the HLMI beinglow, e.g., lower than about 60.

Run numbers 38-44 of Table 1 illustrate polymerization using catalystprepared in accordance with Example 9 wherein the vanadium compound wasVOCl₃, the zirconium compound was Zr(OC₃ H₇)₄ . nC₃ H₇ OH and thevanadium to zirconium ratio was 2. The catalyst exhibited highreactivity with both CHCl₃ and CFCl₃ as modifiers. A comparison of Runnumbers 38 and 40 with Run numbers 39 and 41, respectively, shows thatwhen the concentration of modifier was increased, the MI potentialincreased.

Run numbers 45-50 of Table 1 illustrate polymerization using catalystprepared in accordance with Example 10. The catalyst showed very highactivity and the polymer thus obtained manifested broad MWD as evidencedby the high MIR. In addition, the molecular weight of the polymer washigh, as gauged by the HLMI being low, e.g., lower than about 60.

The Figure shows the molecular weight distribution curve for the polymerobtained from Run 15, using catalyst prepared in accordance with Example5. As seen by reference to the Figure, the polymer obtained by using thecatalyst of the present invention manifests a bimodal profile. The curveof the Figure was specifically obtained on the basis of gel permeationchromatography (GPC).

The polymers of this invention have many and varied uses, includingformation into films, injection-molded articles and blow-molded articlesusing well-known forming methods. The polymers are contemplated to beespecially useful for forming high-strength films (i.e., films havinghigh impact strength and/or high tear resistance) and injection-moldedand blow-molded articles having high ESCR (i.e., environmentalstress-crack resistance).

The term HLMI, as used herein means the high load melt index as measuredat 190° C. and 21.6 kg in accordance with ASTM D1238-82.

What is claimed is:
 1. A catalyst consisting essentially of the productobtained by admixing:(a) a zirconium composition having the formulaZrX_(a) ¹ (OR¹)_(4-a) wherein X¹ is halogen, R¹ is hydrocarbyl having 1to about 18 carbon atoms and a is 0 or an integer from 1 to 4 andmixtures thereof; (b) a vanadium composition selected from the groupconsisting of compounds having the formula VX_(c) ² (OR²)_(b-c) whereinX² is halogen, R² is hydrocarbyl having 1 to about 18 carbon atoms b isthe valence of vanadium and is 3 or 4 and c is 0 or an integer from 1 tob, VOX_(d) ³ (OR³)_(3-d) wherein X³ is halogen, R³ is hydrocarbyl having1 to about 18 carbon atoms and d is 0 or an integer from 1 to 3, VOX₂ ⁴wherein X⁴ is halogen, and mixtures thereof; and (c) an activatorselected from the group consisting of compounds having the formula ZnX₂⁵ . 2AlR₃ ⁴ wherein X⁵ is halogen, R⁴ is hydrocarbyl having 1 to about12 carbon atoms, Al₂ R₃ ⁶ X⁷ wherein R⁶ is hydrocarbyl having 1 to about12 carbon atoms and X⁷ is halogen, MgR_(f) ⁷ Y_(2-f) wherein R⁷ ishydrocarbyl having 1 to about 12 carbon atoms, Y has the formula OR⁸wherein R⁸ is hydrocarbyl having 1 to 12 carbon atoms or Y is a silylamide having the formula N(SiR₃ ⁹)₂ wherein R⁹ is hydrocarbyl having 1to about 12 carbon atoms and f is 0, 1 or 2, and mixtures thereof. 2.The catalyst of claim 1 wherein R¹, R², R³, R⁴, R⁶, R⁷, R⁸ and R⁹ areeach independently alkyl, cycloalkyl, aryl, aralkyl, alkaryl or mixturesthereof.
 3. The catalyst of claim 2 wherein R¹, R², R³, R⁴, R⁶, R⁷, R⁸and R⁹ are each independently alkyl having 2 to about 10 carbon atoms.4. The catalyst of claim 1 wherein X¹, X², X³, X⁴, X⁵, X⁷ and Y are eachchlorine.
 5. The catalyst of claim 1 wherein said activator is ZnCl₂ .2Al(C₂ H₅)₃, (C₂ H₅)₃ Al₂ Cl₃, (C₄ H₉)₂ Mg, C₄ H₉ MgC₂ H₅, C₄ H₉MgN(Si(CH₃)₃)₂ or mixtures thereof.
 6. The catalyst of claim 1 whereinsaid zirconium compound is ZrCl₄, ZrCl₂ (OC₄ H₉)₂, Zr(OC₃ H₇)₄, Zr(OC₄H₉)₄ or mixtures thereof.
 7. The catalyst of claim 1 wherein saidvanadium compound is VOCl₃, VO(OC₄ H₉)₃, VCl₄, VO(iOC₃ H₇)₃, VOCl₂ ormixtures thereof.
 8. The catalyst of claim 1 wherein for each mole ofzirconium composition, up to about 10 moles of vanadium composition andup to about 25 moles of activator are admixed.
 9. The catalyst of claim8 wherein for each mole of zirconium composition, up to about 8 moles ofvanadium composition and up to about 17 moles of activator are admixed.10. The catalyst of claim 9 wherein for each mole of zirconiumcomposition, up to about 5 moles of vanadium composition and up to about12 moles of activator are admixed.
 11. The catalyst of claim 10 whereinfor each mole of zirconium composition, up to about 3 moles of vanadiumcomposition and up to about 8 moles of activator are admixed.
 12. Thecatalyst of claim 11 wherein for each mole of zirconium composition, upto about 1 mole of vanadium composition and up to about 4 moles ofactivator are admixed.
 13. An olefin polymerization catalyst systemcomprising the catalyst of claim 1 and a co-catalyst of a metal alkyl,metal alkyl hydride, metal alkyl halide or metal alkyl alkoxide, whereinsaid metal is aluminum, boron, zinc or magnesium.
 14. The olefinpolymerization catalyst system of claim 13, wherein the alkyl has 1 toabout 12 carbon atoms.
 15. The olefin polymerization catalyst system ofclaim 13 wherein the co-catalyst is triethyl aluminum or tri-isobutylaluminum.
 16. The olefin polymerization catalyst system of claim 13further comprising a modifier having the formula

    M.sup.1 H.sub.g X.sup.8.sub.h-g

wherein M¹ is Si, C, Ge or Sn, X⁸ is halogen, g is 0, 1, 2 or 3 and hhas the valence of M¹.
 17. The olefin polymerization catalyst system ofclaim 16 wherein said modifier is CCl₄, CH₂ Cl₂, CBr₄, CH₃ CCl₃, CF₂ClCCl₃, CHCl₃, CFCl₃, CFCl₂ CCF₂ Cl, (CH₃)₃ SiCl or mixtures thereof.